The present invention relates to a method of assembling a movable electrode type electric dust collecting apparatus, particularly, to a method of assembling a movable electrode typed electric dust collecting apparatus comprising a large number of discharge frames that are allowed to hang a predetermined distance apart from each other within a casing, and a large number of movable electrodes each consisting of a pair of endless chains and a plurality of dust collecting grids that are attached to said pair of endless chains and arranged to form a loop as a whole, said movable electrodes being arranged to be rotated around every other discharge frame.
A movable electrode typed electric dust collecting apparatus of this kind is known as an electric dust collecting apparatus for removing particles of soot from the waste gas generated from, for example, boilers used in a thermoelectric power plant and from various furnaces in an iron mill. The construction of the movable electrode typed electric dust collecting apparatus, which is widely employed, is schematically shown in FIGS. 4 to 8.
As shown in FIG. 4, a movable electrode typed electric dust collecting apparatus 10 comprises a casing 12, a hopper 13 arranged in a lower portion of the casing 12, a large number of discharge frames 14 arranged within the casing 12, and a large number of movable electrodes 15. A waste gas 17 is introduced through an inlet of a fire flue 16 into the casing 12, and the dust is removed from the waste gas 17 within the casing 12 by the principle of the electric dust collection. Then, the clean waste gas is discharged from within the casing 12 to the outside through an outlet of a fire flue 18. The particles of soot removed from the waste gas 17 drop into the hopper 13 and are taken out of the hopper 13 by a mechanism (not shown) through a discharge port 19.
FIG. 5 is a cross sectional view as viewed in the direction denoted by arrows A in FIG. 4. As shown in the drawing, a large number of discharge frames 14 are allowed to hang a predetermined distance apart from each other within the casing 12. Also, a large number of movable electrodes 15 are arranged to be moved around every two discharge frames 14. FIG. 6 is a side view showing the mounting structure of the discharge frame 14 shown in FIG. 6. FIG. 7 is a cross sectional view as viewed in the direction denoted by arrows B in FIG. 6. The discharge frame 14 includes a large number of discharge wires 21 attached to a lattice-shaped frame body 20. An upper bracket 27 and a lower bracket 28 each extending from each of the discharge frames 14 are mounted an upper stage beam 25 and a lower stage beam 26 of a frame 24 hanging from an insulating tube 22 via a hanging rod 23 to permit the discharge frames 14 to be kept hung. Incidentally, reference numerals 29 and 30 denote a driving wheel and a lower roller, respectively, for driving the movable electrode 15.
FIG. 8 is an oblique view showing in detail the construction of the movable electrode 15. As shown in the drawing, a pair of endless chains 31, 31 are stretched between the driving wheel 29 in the upper portion and the lower roller 30. A plurality of dust collecting grids 32 are attached to these endless chains 31, 31 in the central portions 33 in the width direction of the dust collecting grids 32 to form a loop as a whole. A shaft 34 of the driving wheel 29 is rotated by a driving mechanism (not shown), and the rotation of the shaft 34 is transmitted through the paired endless chains 31, 31 by the driving wheel 29, result in a loopformed-dust collecting grids 32 allowing to be rotated around every other discharge frame 14.
In general, the height of the entire movable electrode typed electric dust collecting apparatus 10 reaches 20 to 30 meters, making it difficult to assemble the entire structure in a factory. Therefore, in assembling the dust collecting apparatus 10, it was customary in the past to build first the casing 12 in the site of installing the apparatus 10, followed by mounting the discharge frames 14 and the movable electrodes 15 within the casing 12.
However, each of discharge frames 14 is suspended by the hanging rods 23 in general 300 to 400 mm apart from each other. What should be noted is that it is necessary to attach to the endless chain 31 of the movable electrode 15 and the dust collecting grid 32 in the small space intermediate between adjacent discharge frames 14, 14 that are incorporated to fill the entire space within the casing 12. A small working space prevent shopman from mounting efficiently these discharge frame 14 and movable electrode 15.
Many steps are required for mounting the discharge frame 14 and the movable electrode 15 within the casing 12, giving rise to various problems. A long hard working conditions causes shopman and operator trouble in operation.
An object of the present invention is to provide a method of assembling a movable electrode type electric dust collecting apparatus, which permits performing efficiently the mounting operation of the discharge frames 14 and the movable electrodes 15 within the casing 12.
According to a first aspect of the present invention, there is provided a method of assembling a movable electrode type electric dust collecting apparatus including a large number of discharge frames that are allowed to hang a predetermined distance apart from each other within a casing and a large number of movable electrodes each consisting of a pair of endless chains and a plurality of dust collecting grids that are attached to said pair of endless chains and arranged to form a loop as a whole, said movable electrodes being arranged to be rotated around every two discharge frames, characterized in that the plural discharge frames are mounted first in predetermined positions within the casing, followed by mounting the plural movable electrodes.
The present invention is featured in that, for mounting the discharge frames and the movable electrodes, the discharge frames and the movable electrodes are introduced into predetermined positions within the casing through the open portion of the hopper before the hopper is mounted in a lower portion of the casing, followed by mounting the hopper.
The present invention is also featured in that a rail is arranged on the upper surface of the casing, and a gate-shaped movable crane capable of running along the rail is utilized for mounting the discharge frames and the movable electrodes in predetermined positions.
The present invention is also featured in that the process for mounting the movable electrode comprises the steps of forming first the movable electrode in a linear form, pulling up both end portions of the linear movable electrode simultaneously or separately through the open portion of the hopper to a ceiling position within the casing, and joining the both end portions of the linear movable electrode to each other in the ceiling position to form a loop of the movable electrode.
The present invention is further featured in that the process of forming the movable electrode comprises the steps of forming first the movable electrode in the form of two parts substantially equal to each other in length, bringing these parts of the movable electrode to predetermined positions in a lower portion of the casing, pulling up the upper end portion of each of the two parts of the movable electrode through the open portion of the hopper to a ceiling position within the casing, joining the upper end portions of the two parts of the movable electrode to each other in the ceiling position, and joining the lower end portions of the two parts of the movable electrode to each other in a lower position within the casing to form a loop of the movable electrode.
According to the present invention, in assembling a movable electrode typed electric dust collecting apparatus including a large number of discharge frames that are allowed to hang a predetermined distance apart from each other within a casing and a large number of movable electrodes each consisting of a pair of endless chains and a plurality of dust collecting grids that are attached to said pair of endless chains and arranged to form a loop as a whole, said movable electrodes being arranged to be rotated around every two discharge frames, the mounting operation of these discharge frames and movable electrodes can be performed efficiently within the casing.